Cationic surfactants have long been known as useful additives in laundry detergent compositions for the purpose of providing the laundered fabrics with a static control benefit (see e.g., U.S. Pat. No. 3,951,879, Wixon, issued Apr. 20, 1976, and U.S. Pat. No. 3,959,157, Inamorato, issued May 25, 1976, both of which are incorporated herein by reference), a fabric softening benefit (see e.g., U.S. Pat. No. 3,607,763, Salmen et al, issued Sept. 21, 1971, U.S. Pat. No. 3,644,203, Lamberti et al, issued Feb. 22, 1972, and U.S. Pat. No. 3,537,993, Coward et al, issued Nov. 3, 1970, all of which are incorporated herein by reference), or a sanitization benefit (see e.g., U.S. Pat. No. 2,742,434, Kopp, issued Apr. 17, 1956, U.S. Pat. No. 3,539,520, Cantor et al, issued Nov. 10, 1970, and U.S. Pat. No. 3,965,026, Lancz, issued June 22, 1976, all of which are incorporated herein by reference). However, it is only very recently that it has been discovered that by combining specific types of cationic surfactants with a narrowly defined range of alcohol ethoxylate-type nonionic surfactants, within defined nonionic:cationic ratios, simple, unbuilt detergent compositions, which deliver outstanding cleaning performance, may be formulated (see e.g., U.S. Patent Application Ser. No. 919,181, Murphy, filed June 26, 1978, U.S. Patent Application Ser. No. 919,341, Cockrell, filed June 26, 1978, and U.S. Patent Application Ser. No. 885,931, Murphy, filed Mar. 13, 1978, now abandoned all of which are incorporated herein by reference). However, when these compositions are formulated, since the nonionic:cationic ratio for optimum removal of greasy/oily soils is generally different from that required for optimum removal of particulate soils, it is necessary to either sacrifice optimum removal of one soil type in order to obtain optimum removal of the other type, use additional components, such as the amides disclosed in U.S. Patent Application Ser. No. 919,340, Cambre, filed June 26, 1978, incorporated herein by reference, to enhance soil removal, or else choose an intermediate nonionic:cationic ratio at which excellent, but not optimum, cleaning for both types of soils is obtained.
It has now been found that by using a specific type of cationic surfactant (i.e., single long chain alkyl quaternary ammonium materials) in nonionic/cationic surfactant systems, the optimum nonionic:cationic ratios for clay and grease/oil removal can be made to coincide or at least be close enough to each other to permit optimum removal of both types of soil with a single detergent composition, while also providing static control, softening, color fidelity, and dye transfer inhibition benefits to fabrics laundered therewith. The level of particulate and greasy/oily [especially fatty acid-derived soils (such as triolein) on polyester fabrics] soil removal achieved by the compositions of the present invention, even when formulated without builders, is outstanding.
It is, therefore, an object of this invention to provide low or no phosphate laundry detergent compositions which simultaneously demonstrate outstanding removal of both particulate and greasy/oily soils.
It is another object of this invention to provide laundry detergent compositions, containing cationic and nonionic surfactants, which yield optimum clay removal and optimum greasy/oily soil removal at approximately the same nonionic:cationic ratio.
It is yet another object of this invention to provide laundry detergent compositions, yielding excellent particulate and greasy/oily soil removal, which may conveniently be produced in a variety of physical forms, such as liquid, solid, paste, granular, powder, or in conjunction with a carrier, such as a substrate.
It is further object of this invention to provide a single composition which yields outstanding cleaning performance together with fabric softening, static control, color fidelity, and dye transfer inhibition benefits.
It is a still further object of this invention to provide a process for laundering fabrics which yields exceptional particulate and greasy/oily (especially fatty acid-derived) soil removal, over a range of water hardness conditions, using cationic and nonionic surfactant-containing detergent compositions.